Medium Duty Operator's Manual - Peterbilt Motors Company

Preventive Maintenance
STEERING AND DRIVELINE
Power Steering
Oil (under low pressure) provides the power to operate the
steering gear. It also serves to lubricate moving parts and
remove heat. A loss of steering efficiency will occur if too
much heat builds up in the system.
WARNING! Do not operate the vehicle if the
steering system is not working properly. You
could lose control of your vehicle if the steering
system is not in good working condition, which
could result in a serious injury accident. For
driving safety, visually check the steering gear
and components. Frequent checks are important
for driving safety, especially after traveling
over rough roads.
NOTE: If the steering feels unbalanced from side-toside
while turning, check for the following possible
causes:
• unequal tire pressures
• vehicle overloaded or unevenly distributed load
• wheels out of alignment
• wheel bearings improperly adjusted
Steering and Driveline
If you cannot correct the problem, check with an Authorized
Service Center.
The Medium Duty is equipped with integral power steering.
The system includes an engine-driven fluid pump, a fluid reservoir,
the steering gear, and connecting hoses. Because of
the hydraulic power assist, little effort is required to turn the
steering wheel. When no input is applied through the steering
wheel, the steering gear will return to the neutral position.
If, for any reason, the power assist system goes out, steering
the vehicle is still possible—yet it will require much greater
effort.
Visually check the following parts:
• Crosstube: Is it straight?
• Draglink tube clamp: Check for looseness or interference.
• Ball joints and steering U–joints: Check for looseness.
• Steering wheel for excessive free-play. Check the simplest
probable causes first:
– unequal tire pressures
– loose cap nuts
– bent crosstube
– lack of lubrication
Medium Duty (R05/09) Y53-6008A – 237 –